Why are the gcc-*-base packages priority:required?

[Theodore Ts'o <tytso@mit.edu>]

Potentially stupid question --- why are the gcc-4.[789]-base packages
have the priority required?  And what are they used for?

I'm fine-tuning a small kvm appliance (kvm-xfstests, as it happens), and
I'm trying to keep the root file system as small as possible.  It
appears that I can dpkg --purge the gcc-4.[789]-base packages with no
ill effects.

Am I missing something subtle that will come back and bite me?

Thanks,

                                                - Ted